Automatic air-brake test signal



Feb. 21,1928. 1,659,884

H. B. MARCUM AUTOMATIC AIR BRAKE TEST SIGNAL Filed-Aug. 22, 1927 IN VEN TOR.

% g M ATTORNEYS.

Patented Feb. 21, 1928.

HARVEY LB. MARCUM, OF DODGE CITY, KANSAS.

AUTOMATIC AIRrBRAKE TEST SIGNAL.

Application filed August 22, 1927. Serial No. 214,623.

This invention relates to automaticair brake signals, and more particularly to a signal for use on the caboose on a freight train, which can be readily seen by theconductor and engineer in charge of the train. Certain railroad rules require, after each stop of a train from which the engine has been detached or a car cut out, the testing of the air line before the train proceeds, so that the train crew may know absolutely whether or not the air line is open and working through the entire length of the train for the proper automatic operation of the brakes. It is also required that the brakeson each individual car shall be inspected after the tests to make sure that they have allbeen released prior to the departure of the train, and present practice demands that one of the train crew shall walk to the rear end of the train and then watch and see that the brakes set and release on the rear car in the train, that is the caboose thereof, as the engineer tests the air line by throwing the brakes on and 01f. If the brakes release when thrown ofi by the release of the air, it is apparent that the air line is in proper condition throughout the entire length of the train. Time is lost if one is required to walk to the rear end of the train for the test of the air line, as the conductor can use this man to a great advantage to stand at the opposite side of the train as .it pulls out, thus providingjfor inspection from both sides, to see that all brakes have released and other running material is in proper working-order.

It has been heretofore proposed to .pro-

vide a signal on the caboose, visible .to the engineeron the locomotive, or any member of the'crew' who may beat any place on or near the train, for the purpose of indicating that the brakes set and release on the last car in the train, and that the air line is open throughout the train, but in such application-of the signal'it was contemplated toconnect the signal to the brakemechanism for the positive response to bothon and off operations of the brakes, in which case the springs which return thevbrake cylindervpistons to normal upon the release of the air would be required to not only operate the signal to clear position but also perform the work of operatingthe brake levers to withdraw the brake shoes fromthe wheels. It has heenfound in actual tests that to impose this additional burden on the springs so 'sure, be turned to full clear position, be-

cause the reaction of the brakes when released would, not return them to full release position, as that occurs in the present practice, under the-jolting to which they are sub jected by the running of the train, because the brake cylinder piston and brake-actuating rod move out of contact on the release of the pistons. It thus appears that with the old type of signal mentioned as proposed, the air line might be properly open for the full length of the train and yet the signal would not clearly indicate that fact, and under such conditions time would perhaps be lost by manual inspection before the engineer would be authorized to proceed. I have found that the arrangement of the character outlined, which was first proposed more than forty years a 0, would not be acceptable to those in c arge of air brake equipment, because of uncertainty in operation, but that the signal can be operated dependably, provided it is divorced from the air brake lever connections and instead connected positively to the brake cylinder piston sleeve of the modern equipment. By this arrangement, when the engineer sets or releases the air, if all of the connections are in order and the air line is open, all of the pistons will return under the pressure of their respective springs, toward the head ends of the cylinders, and the signal will invariablyrbe turned to full clear position. The brakes independently of the signal, react when the air is released without material movement, but suflicient to disengage the brake shoes from the wheels, and

as above stated after the train is in motion,

are jolted back to full release position, so

that the brake levers operating the rods shall be positioned to respond instantly upon the nextapplication of air upon the brake cylinder pistons and thus positively engage the wheels. This signal cannot be successfully operated by attaching it to the brake rod or levers, nor can the brake rodjand piston be riveted together and worked with this signal as it imposes too much work on the brake cylinder springs to pull the brake levers into running position. It also interforce with the use of the hand brakes on the caboose as it is necessary to pull against the spring to set the hand brakes should the brake rod and piston be riveted together. Apparatus of the character first proposed was given a practical test some months ago on the Atchison, Topeka and Santa Fe Railroad system, and was found to be objectionable. The desirability of a dependable signal was so great however, that a solution of the problem was sought, and I found, after some experiments, that by entirely divorcing the signal from direct connection with the brake rod or brake lever mechanism, and connecting it to the brake cylinder piston sleeve,.the signal would invariably turn to clear position the instant the air was released on the car, and such equipment has already been applied to about ten of the Atchison, Topeka and Santa Fe Railroad Companys cabooses and is working successfully, and it is expected that it will be ordered on all the freight trains on the system mentioned, as it not only provides for great or efficiency and safety in operation of such trains but also materially reduces the cost of operation, and effects a material saving of time in the movement of trains. A conductor should know before leaving any point Where air has been cut out or an engine or car has been detached from the train, that he has air Working throughout his train so as to be able to stop the train with his brake valve from the rear end in any car in cases where necessary to stop, as usually in emergency cases, and it is the purpose of this signal to indicate to him after coupling train and cutting air in, that he has air Working on the rear car of his train without sending a man back to see that it sets and releases on the caboose.

Accordingly, this invention has for its object to produce a visual signal for use pri- -marily at the rear end of a freight train, to

unfailingly indicate to the conductor and engineer whether or not the air line is open and working throughout the length of the train, and in order that the invention may be fully understood, reference is to be had to the following description, appended claims and the accompanying drawing, 1n

which:

Figure l is a side elevation of a freight train caboose equipped with a signal embodying the invention, the brake cylinder being shown as enclosed in a housing and of exaggerated size.

Figure 2 is a horizontal section taken be low the floor of the caboose, and indicating the outline of the latter indotted lines.

Figure 3 is a view partly in side elevation and partly in vertical section, showing what is known as a combined freight brake equipment, and also shows the signal operating link connected to the stem of the piston of the brake cylinder but not connected with the rod upon which the cylinder operates rectly to th e cylinder. In both cases, however, there is an air supply pipe 3 for transmitting air from the triple valve, not shown, of the auxiliary reservoir to the brake cylinder to operate the piston thereof, the air passing in the reverse direction through said pipe to permit of the return of the piston. The piston is provided with a tubular stem 5, and a coil spring 6 surrounds the stem I and bears at the opposite ends against the piston and the rear end of the air brake cylinder, the function of'said spring being to return the piston to normal position upon the air release operation of the triple valve, as customary and conventional in air brake systems. Indicated in dotted lines in F igare 3, is a rod-7 having a forked end pivotfits in the tubular stem so that when the air is applied through pipe 3, and the piston is moved rearward in the air cylinder, the said rod is operated to effect application of the brakes, It will also be noted that when the air is released and the piston is returned to normal position by the spring 6, the pressure is removed from the rod and the latter is not positively drawn back with the piston but is left free to returnto normal position under the reaction of the brake mechanism and the jolting of the train.

As thus far described, the mechanism is of conventional type in air brake systems for freight cars, and to provide a dependable signal and one which will invariably respond to the operations of the piston, a link 10 is pivotally connected at one end to the piston stem 5 and at its other end to a crank 11 secured on the lower end of a shaft or staff 12 extending up through and to a suitable distance above the top of the oaboose, and said shaft carries a signal disk 13 which, when the air line is opened throughout the full length of the train, stands edgewis'e to the front and rear of the train and hence indicates to the conductor readily see it operate. regardless of the length of the train, are released can see the signal go back to clear position before the train should be started. If the engineer cannot turn it to clear position by releasing the' air, then it is necessary to make an investigation 'to find the source of the trouble. For use at night, the stafl also carries a lantern or the like 14 which will be provided with bullseye lenses of different colors. A white light at front and rear indicates that the air is set on the caboose. A green light at front and rear indicates air is released on the caboose. The details of the light, which may be of any conventional type, are not illustrated.

From the above description, it is apparent that I have produced a signal mechanism embodying the features of advantage set forth as desirable in the statement of the object of the invention and which is susceptible of modification in minor particulars without departing from the principle of construction and mode of operation involved or from the spirit and scope of the appended claims.

I claim:

1. The combination with a car equipped with an air brake cylinder, a piston in the cylinder movable longitudinally of the latter by admitting air to the cylinder, a hollow piston rod projecting through one end of the cylinder, a spring for reversing the movement of the piston when the air is released from the cylinder, a rotary target on the car, and means for transmitting power from the hollow piston rod to the target to and when the brakes.

operate'the latter in one direction or the other according to travel of the piston.

2, The combination with a car of a vertical staff journaled on the car and projecting upward from the top thereof, a signal target rigidly secured to the staff at a point above the car, an air brake cylinder carried by the car, a piston in the. air brake cylinder, a hollow piston rod projecting through one end'of the cylinder, connections between the said hollow rod and the staff to turn the latter when the piston is operated by air supplied to the cylinder, and a spring to return the piston to its original position when the air is released from the cylinder and incidently reverse themovement of the signal shaft.

3. The combination with a car equipped with an air brake cylinder, a piston in the cylinder operated in one direction by air pressuresupplied to the cylinder, a piston rod projecting through one end of the cyllinder, a spring to return the piston to normal position upon release of the air from the cylinder, a brake rod co-operating with the piston for movement thereby only when air is admitted to the cylinder, of a signal mounted upon and exposed exterior to the car, and connections between the signal and piston rod whereby operation of the piston by air shall turn the signal in one direction and operation of the piston by the spring shall return the signal to its original position.

In testimony whereof I affix my signature.

HARVEY B. MARCUM. 

